Vidhisha Jassal

Recent strategies for removal and degradation of persistent & toxic organochlorine pesticides using nanoparticles: A review

Organochlorines (OCs) are the most hazardous class of pesticides, therefore, banned or restricted in several countries. The major sources of OCs include food industries, agriculture and sewage wastes. Their effluents discharged into the water bodies contain extremely high concentration of OCs which ultimately causes environmental concern. Because of their high persistence, toxicity and potential to bioaccumulation, their removal from wastewater is imperative. The degradation techniques are now advanced using nanomaterials of various kinds. During the last few years, nanoparticles such as TiO2 and Fe are found to be excellent adsorbents and efficient photocatalysts for degrading more or less whole OCs as well as their toxic metabolites, which opens the opportunities for exploring various other nanoparticles as well. It is noteworthy that such methodologies are economic, fast and very efficient. In this review, the detailed information on different types of OC pesticides, their metabolites, environmental concern and present status on degradation methods using nanoparticles have been reviewed. An attempt has also been made to highlight the research gaps prevailing in the current research area.

Green synthesis of potassium zinc hexacyanoferrate nanocubes and their potential application in photocatalytic degradation of organic dyes

A novel green route was used to synthesize potassium zinc hexacyanoferrate (K2Zn3[Fe(CN)6]2·9H2O) (KZnHCF) nanocubes using Sapindus mukorossi as a natural surfactant and water as the solvent. The synthesized nanoparticles were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), thermogravimetric techniques and BET surface area analysis. KZnHCF nanoparticles were investigated for their effect on the photocatalytic degradation of two synthetic dyes namely Eriochrome Black T (EBT) and Malachite Green (MG). The effect of process parameters like pH, temperature, KZnHCF dose and concentration of the dye on KZnHCF mediated degradation of both dyes was also investigated. Under optimized conditions, KZnHCF resulted in 94.15% degradation of MG followed by 76.13% EBT degradation.

Degradation of hazardous organic dyes in water by nanomaterials

There is about 700,000 tonnes of dyes, of more than 10,000 types, that are used as coloring agents in industries, mainly for textile. The release of dyes in natural media is of concern due to their high persistence, toxicity and potential to the bioaccumulate in living organisms. In particular, the most commercialized and carcinogenic azo dyes, that pocess a benzidine function, needs urgent attention. Here, we review the current status of cationic and anionic dyes. We present dye removal techniques using nanoparticles through adsorption and degradation. Among dye removal techniques, adsorption was found the most efficient and cheap. For that, conventional adsorbents such as commercial activated carbon, chitosan and natural waste are often employed. We discuss the use of ZnO, TiO2 and Fe0 to remove dye pollution.

Aegle marmelos Mediated Green Synthesis of Different Nanostructured Metal Hexacyanoferrates: Activity against Photodegradation of Harmful Organic Dyes

Prussian blue analogue potassium metal hexacyanoferrate (KMHCF) nanoparticles Fe4[Fe(CN)6]3 (FeHCF), K2Cu3[Fe(CN)6]2 (KCuHCF), K2Ni[Fe(CN)6]·3H2O (KNiHCF), and K2Co[Fe(CN)6] (KCoHCF) have been synthesized using plant based biosurfactant Aegle marmelos (Bael) and water as a green solvent. It must be emphasized here that no harmful reagent or solvent was used throughout the study. Plant extracts are easily biodegradable and therefore do not cause any harm to the environment. Hence, the proposed method of synthesis of various KMHCF nanoparticles followed a green path. The synthesized nanoparticles were characterized by powder X-ray diffraction (PXRD), Field-Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FT-IR). MHCF nanoparticles were used for the photocatalytic degradation of toxic dyes like Malachite Green (MG), Eriochrome Black T (EBT), Methyl Orange (MO), and Methylene Blue (MB). Under optimized reaction conditions, maximum photocatalytic degradation was achieved in case of KCuHCF nanoparticles mediated degradation process (MG: 96.06%, EBT: 83.03%, MB: 94.72%, and MO: 63.71%) followed by KNiHCF (MG: 95%, EBT: 80.32%, MB: 91.35%, and MO: 59.42%), KCoHCF (MG: 91.45%, EBT: 78.84%, MB: 89.28%, and MO: 58.20%).

Towards green synthesis of nanoparticles: From bio-assisted sources to benign solvents. A review

ABSTRACT Current advancements in green synthesis of materials especially nanoparticles have led to conservation of natural and non-renewable resources along with reduction in environmental pollution. Development of cost-effective, simple and eco-friendly routes for the synthesis of nanoparticles is very important. All over the world, a wide variety of biogenic sources have been put to trial as a source of green agents to facilitate synthesis process. In addition to this, environmentally benign solvents are also being used these days in order to promote green synthesis. In this review, an attempt has been made to familiarise the readers with the different green routes for the synthesis of nanoparticles.

Synthesis, Characterization and Applications of Nano-structured MetalHexacyanoferrates: A Review

The present paper offers a review of recent work on synthesis, in situ , and applications of few metal hexacyanoferrate nanoparticles with the general formula M4[Fe(CN)6].xH2O where M is transition metal. Five such metal hexacyanoferrates (MHCF’s) compounds derived from Co, Zn, Fe, Cu and Ni with general introduction followed by synthesis, properties and applications of individual hexacyanoferrate nanoparticles have been featured in this article. In addition, the characterization of aforesaid nanoparticles using instrumental techniques like SEM, TEM and XRD have also been discussed.

Catalytic removal of organic colorants from water using some transition metal oxide nanoparticles synthesized under sunlight

Transition metal oxides (TMO) constitute a most amazing class of materials with a wide range of properties and applications; therefore, their synthesis using a green approach is a necessity. As such, sunlight irradiation was employed to synthesize various TMO nanostructures (ZnO, CuO, Co3O4, NiO and Cr2O3) using water as a solvent. Nanoparticles obtained with distinct morphologies, such as nanotubes (ZnO; 86.86% (CuO) > 85.89% (NiO) > 80.35% (Co3O4), depending on the sizes of the respective TMO nanoparticles. This is also supported by the finding of small and non-toxic by-products such as but-2-enal, sulfur trioxide and benzoquinone. With high potential observed in the removal of dyes, TMO nanoparticles have a bright future with respect to their use as important adsorbents in waste water treatment. The advantage of the present work lies in the green synthesis of nanoparticles and their application in helping to make our environment green.

Fabrication of green device for efficient capture of toxic methylene blue from industrial effluent based on K2Zn3[Fe(CN)6]2·9H2O nanoparticles reinforced gum xanthan-psyllium hydrogel nanocomposite

In the present work, the synthesis of novel device for the efficient removal of toxic cationic dye methylene blue (MB) from aqueous fluid was carried out. The device was fabricated by in-situ incorporation of K2Zn3[Fe(CN)6]2·9H2O nanoparticles into gum semi-IPN matrix in the presence of glutaraldehyde-ammonium persulphate as crosslinker–initiator system. The effect of several reaction variables such as time, solvent, temperature, pH, crosslinker, initiator concentration and monomer concentration on the fluid uptake capacity of the candidate sample was explored. The morphological and structural properties were studied using Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction studies. Thermal stability was evaluated by thermogravimetric analysis/differential thermal analysis/differential thermogravimetric analysis. Contact time, adsorbent dose and initial concentration of dye solution were optimized for maximum dye removal and it was ...